The objective of this study is to identify factors in infancy and early childhood which are associated with higher probability of later emotional or cognitive difficulties. This study will focus primarily, but not exclusively on aspects of the mother-infant interaction and infant functioning which have been hypothesized to be predictive of deviant development outcome during early childhood. It is hypothesized that only those children who show several, perhaps all, of these factors, will be at risk for later emotional or cognitive difficulties. This research strategy recognizes that there may be multiple manifestations of early difficulties, and the question is whether the extensiveness of these problems is a better predictor than any single index.